FACTBOX: Presidential candidates and gun control

(Reuters) - The Supreme Court's ruling on Thursday that Americans have the right to own guns for personal use could become an issue in the U.S. presidential race.

Here are the positions of the two candidates in November's election:

DEMOCRATIC CANDIDATE SEN. BARACK OBAMA

Wants tighter background checks on gun buyers, making gun locks mandatory and holding parents criminally responsible for children who injure someone with a gun found at home. Supports reinstating assault-weapons ban.

The National Rifle Association, a leading advocate of the right to bear arms, gives him a failing grade of F for his position on guns.

REPUBLICAN CANDIDATE SEN. JOHN McCAIN

Opposes gun control, calling it "a proven failure in fighting crime." Opposes waiting periods to buy firearms. Has supported legislation requiring gun makers to include trigger locks with their products. Opposes reinstating assault-weapons ban. Has supported mandating background checks on gun buyers at gun shows.

The National Rifle Association gives him an average grade of C for his position on guns but says he has a perfect voting record since 2007 and his grade may be revised.

Sources: Reuters, campaign Web sites, Detroit Free Press, the National Rifle Association

(Compiled by Paul Grant, Washington Editorial Reference Unit; editing by Frances Kerry)